1998 NISSAN PATROL engine

Cooling Circuit
System Check
WARNING:
Never remove the radiator cap when the engine is hot; serious
burns could be caused by high pressure ¯uid escaping from
the radiator.
Wrap a thick cloth around cap and carefully loosen it a quar-
ter turn to release built-up pressure. Then remove the cap
completely.
CHECKING COOLING SYSTEM HOSES
Check hoses for proper attachment, leaks, cracks, damage, loose
connections, cha®ng and deterioration.
CHECKING RADIATOR CAP
Apply pressure to radiator cap by means of a cap tester to see if it
is satisfactory.
Radiator cap relief pressure:
78-98kPa
(0.78 - 0.98 bar, 0.8 - 1.0 kg/cm
2, 11 - 14 psi)
SLC226A
SLC613
ENGINE COOLING SYSTEM
LC-9

Pull the negative pressure valve to open it. Check that it closes
completely when released.
CHECKING COOLING SYSTEM FOR LEAKS
Apply pressure to the cooling system by means of a tester to check
for leakage.
Testing pressure:
98 kPa (0.98 bar, 1.0 kg/cm
2, 14 psi)
CAUTION:
Use of pressure higher than the speci®ed value may cause
damage to radiator.
Water Pump
CAUTION:
+When removing water pump assembly, be careful not to
get coolant on drive belts.
+Water pump cannot be disassembled and should be
replaced as a unit.
+After installing water pump, connect hose and clamp
securely, then check for leaks using radiator cap tester.
REMOVAL
1. Drain coolant from radiator and cylinder block.
Cylinder block drain plug (Use proper sealant):
:34-44Nzm (3.5 - 4.5 kg-m, 25 - 33 ft-lb)
Refer to MA section (``Changing Engine Coolant'', ``ENGINE
MAINTENANCE'').
2. Remove radiator shroud.
3. Remove drive belts. Refer to MA section (``Checking Drive
Belts'').
4. Remove fan coupling with fan.
5. Remove water pump.
SMA967B
SMA007D
SMA003D
ENGINE COOLING SYSTEM
System Check (Cont'd)
LC-10

INSPECTION
1. Check for rusted or corroded body assembly and vane.
2. Check for excessive end play and rough operation.
INSTALLATION
+Remove liquid gasket from mating surface of pump housing
using a scraper.
Be sure liquid gasket in grooves is also removed.
+Remove liquid gasket from mating surface of cylinder block.
+Clean all traces of liquid gasket using white gasoline.
+Cut off tip of nozzle of liquid gasket tube at point shown in ®g-
ure.
+Use Genuine Liquid Gasket or equivalent.
SLC997-A
SLC998
SLC822
ENGINE COOLING SYSTEM
Water Pump (Cont'd)
LC-11

+Apply a continuous bead of liquid gasket to mating surface of
pump housing as shown.
a. Be sure diameter of liquid gasket is within 2.0 to 3.0 mm
(0.079 to 0.118 in) dia. range.
b. Attach pump housing to cylinder block within ®ve minutes
of applying liquid gasket.
c. After installing pump housing, wait at least 30 minutes
before starting engine.
Thermostat
INSPECTION
1. Check valve seating condition at ordinary temperatures. It
should seat tightly.
2. Check valve opening temperature and maximum valve lift.
Valve opening temperature CÉ (ÉF) 82.0 (180)
Maximum valve lift mm/ÉC (in/ÉF) 10/90 (0.39/194)
3. Then check if valve closes at 5ÉC (9ÉF) below valve opening
temperature.
INSTALLATION
+Remove liquid gasket from mating surface of thermostat using
a scraper.
+Similarly, remove liquid gasket from mating surface of cylinder
block.
+Clean all traces of liquid gasket using white gasoline.
SLC001A
SLC002A
SLC343
SLC790
Scraper
ENGINE COOLING SYSTEM
Water Pump (Cont'd)
LC-12

+Cut off tip of nozzle of liquid gasket at point shown in ®gure.
+Use Genuine Liquid Gasket or equivalent.
+Apply a continuous bead of liquid gasket to mating surface of
water inlet.
a. Be sure diameter of liquid gasket is within 2.0 to 3.0 mm (0.079
to 0.118 in).
b. Attach water inlet to cylinder block within ®ve minutes after
applying liquid gasket.
c. After installing water inlet, wait at least 30 minutes before re®ll-
ing coolant and starting engine.
SLC822
SLC824 Diameter of liquid gasket:
2.0 - 3.0 mm (0.079 - 0.118 in)
ENGINE COOLING SYSTEM
Thermostat (Cont'd)
LC-13

Radiator
REMOVAL AND INSTALLATION
1. Remove under cover.
2. Drain coolant from radiator drain plug.
3. Disconnect radiator upper and lower hoses.
4. Remove radiator lower shroud.
5. Disconnect reservoir tank hose.
6. Remove radiator.
7. After repairing or replacing radiator, install any part removed in
reverse order of removal.
Re®lling Engine Coolant
For details on re®lling engine coolant, refer to MA section (``REFILL-
ING ENGINE COOLANT'', ``Changing Engine Coolant'').
SLC198B
ENGINE COOLING SYSTEM
LC-14

Cooling Fan (Crankshaft driven)
DISASSEMBLY AND INSTALLATION
+Do not release the drive belt tension by removing the fan/water
pump pulley.
+Fan coupling cannot be disassembled and should be replaced
as a unit. If front markj
Fis present, install fan so that side
markedj
Ffaces the front.
+Install the drive belt only after the fan and fan coupling to water
pump ¯ange bolts/nuts have been properly torqued.
+Proper alignment of these components is essential. Improper
alignment will cause them to wobble and may eventually cause
the fan to separate from the water pump causing extensive
damage.
INSPECTION
Check fan coupling for damage, oil leakage and bent bimetal.
Cooling Fan (Motor driven)
Cooling fan is controlled by ECM. For details, refer to ``Cooling
Fan'', ``TROUBLE DIAGNOSIS FOR DTC 28'' in EC section.
SLC176B
SLC072
SLC177B
ENGINE COOLING SYSTEM
LC-15

Radiator (Aluminum type)
Aluminum radiator can be disassembled by using special proce-
dures and special service tools.
DISASSEMBLY
1. Remove tank with Tool.
+Grip the crimped edge and bend it upwards so that Tool slips
off.
Do not bend excessively.
SLC882AB
SLC903
SLC893
ENGINE COOLING SYSTEM
LC-16